OP JAMES SMITHSON. 149 



crystals of quartz, and contains pyrites disseminated in it, which are 

 probably auriferous. ' 



No. 25.— Arseniate of iron. Paris, September 25, 1820. 



r>f InSu"!''?'.'!-'^^' ^»* °r ^°^''?^ native arsenuret of cobalt to form nitrate 

 t:?' U'w\"s'wa,;be7"nd dHo^ " ' ^"'^^^"^ ^'"^^^^ ^^^'^' ^ ''^ --" 

 J<ia^Zt'r:::l:l-Z'.'''''' '"' -ystalsof arsemous acid sublimed 



8. This dark mass boated on coal at the blow-pipo omitted fumes prob- 

 Sol^cffLtTt'"'""' ^°°"°° ^'''' " '°°"* °' '^°"' ''"^ ^''° magncnid 



4 The scoria-liltoniass dissolved in borax with effervesence and spread 

 muchonthec^al. This glass in the whole looked black, but where there 

 were air-bubbles it had the color of chrysoberyl 



qufclJybecalTyXw"''^ '" ''"^' muriatic acid in a tube. The acid 



Unr'f,Tu^''^V^[^ ''"." ^"T"*^ «" abundant precipitate of prussian 

 r 1 if "'^'■"^° ^f «''^" f"'-'"^^ only a white curdy precipitate of chlo^ 

 ride of silver, and no arseniate of silver. •' *- i 



^^nft^ J'/^^*'''®' *'°^«^«'"' t^"*' the above yellow powder is arseniate or ar- 

 "Soiiit© oi iron. 



Ko. 965.— Paris, May, 1819. 



tol^'fl^om DaJ^Se""'' '"'"'"^"^ ''" '' ^^"^' "°"'^*"'^ ''^''^ ^^^ =-d 

 Both the black fibrous part and the white part, when held in the flamo 



of a candle, take firo and burn with a large flame 



When the white part was tried, a fluid matter like oil flowed from it and 



n'n fl^ T' greenish, and it was soft and brittle like spermacite. 



No foetid animal smell was perceived during the combustion, 

 ihe matter is more like adiposcere than mountain cork. 



No. 1166. Octahedral crystals from Clausthal. 



1. These crystals are easily broken, 

 chang^e"' '''*° ^"'"'' """""^'^ "'''^' ^^® fragments of it did not suflFer any 



♦« o ^uu^^' ^* ^^^ blow-pipe they did not decrepitate, but readily reduced 

 to a white metal, which exhaled. caui.jr leuucea 



r>ft 3^? *^'T'/^ '" *'"'^'' "^'i^ effervescence, without coloring it. Balls 

 of a white meta were produced, but when the borax became fluid it soaked 

 into the charcoal like alkali, and the whole disappeared. 

 ^^5. Ihe form of the crystals is regular octahedral, with the six points cut 



6. Their color is gray, and their aspect metallic. 



♦l,!'«J, r''/''"''*" mu'' P«'"f««i'y tubular and parallel to the six corners of 

 the octahedron. Their true form is a cube, fissile, parallel to its six faces. 

 N. B.— These are, most probably, common sulphuret of lead. 



No. 1664.— Native gold from the Edder, a river in Hessia. 

 in Germany. ' 



I had it from Capt. Stockhausen's cabinet. 

 N. B. — It is only mica. 



